King Ash Bay 2012 - 307 Visitors to King Ash Bay 2012- 3,500 - 5,5008 (Not Including Cabins, Lodge and Houseboats)
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McArthur River Monitoring Bill Sawynok, Wendi Parsons and John Platten Infofish Australia, PO Box 9793, Frenchville, Queensland 4701 McArthur River Monitoring page 1 Published by Infofish Australia © Infofish Australia December 2012 This work is copyright. Except as permitted under the Copyright Act 1968 (Commonwealth), no part of this publication may be reproduced by any process, electronic or otherwise, without the specific written permission of the copyright owners. Neither may information be stored electronically in any form whatsoever without such permission. DISCLAIMER The authors do not warrant that the information in this report is free from errors or omissions. The authors do not accept any form of liability, be it contractual, tortuous or otherwise, for the contents of this report or for any consequences arising from its use or any reliance placed upon it. The information, opinions and advice contained in this report may not relate to, or be relevant to, a reader's particular circumstances. Opinions expressed by the authors are the individual opinions of those persons and are not necessarily those of the publisher or research provider. Cover designed by Creative Avenue Rockhampton TABLE OF CONTENTS McArthur River Monitoring page 2 ACKNOWLEDGEMENTS ..................................................................... 5 SUMMARY ....................................................................................... 6 1. BACKGROUND .......................................................................... 10 2. PROJECT OBJECTIVES................................................................ 10 3. PROJECT AREA.......................................................................... 11 4. FISHING CHARACTERISTICS....................................................... 11 5. WHAT INFLUENCES FISHING?..................................................... 13 6. WHO GOES FISHING? ................................................................ 16 7. WHEN DO THE3Y GO FISHING?................................................... 17 8. WHERE DO THEY GO FISHING?................................................... 18 9. WHAT IS A TYPICAL FISHING TRIP?............................................. 20 10. HOW MANY FISHING TRIPS?..................................................... 22 11. WHAT IS THE CATCH?.............................................................. 27 12. FISHING COMPETITIONS .......................................................... 31 13. BARRAMUNDI TAGGING ........................................................... 32 14. BARRAMUNDI GROWTH............................................................ 37 15. BARRAMUNDI MOVEMENT......................................................... 38 16. BARRAMUNDI SIZES ................................................................ 41 17. BARRAMUNDI RECRUITMENT .................................................... 43 18. ELECTROFISHING SURVEYS...................................................... 45 19. GOLDEN SNAPPER TAGGING..................................................... 47 20. COMPARISIONS WITH OTHER RIVERS........................................ 50 21. DISCUSSION .......................................................................... 52 22. COCLUSIONS .......................................................................... 54 23. APPENDIX 1............................................................................ 55 24. APPENDIX 2............................................................................ 56 FIGURES Figure 1: McArthur River project area........................................................................................11 Figure 2: Commercial netting closures adjacent to the McArthur River...........................................12 Figure 3: Monthly rainfall at Borroloola and Centre Island ............................................................13 Figure 4: Wet season rainfall at Borroloola and Centre Island.......................................................13 Figure 5: Number of days each season where the maximum wind speed exceeded 20 knots at Borroloola and Centre Island....................................................................................................14 Figure 6: Minimum air temperatures at Borroloola from May-August in 2009-2012 .........................15 Figure 7: Fisher trips at King Ash Bay based on state of residence ................................................16 Figure 8: Profile of daily trailer counts (and standard deviation) at the King Ash bay boat ramp ......17 Figure 9: Start and finish times for trips from King Ash Bay boat ramp..........................................18 Figure 10: Destination for fishing trips by season........................................................................19 Figure 11: Locations of fishing trips showing intensity of fishing effort...........................................19 Figure 12: Median length of fishing trips ....................................................................................21 Figure 13: Percentage of days each season when trailer counts were made at the King Ash Bay boat ramp.....................................................................................................................................23 Figure 14: One of the houseboats operating out of King Ash Bay ..................................................24 Figure 15: Estimate of total number of trips each season from winter 2009 to autumn 2012............26 Figure 16: Adjusted catch rates per fishing trip each season ........................................................28 Figure 17: Catch rates of Barramundi each season......................................................................29 Figure 18: Percentage of trips catching Barramundi each season ..................................................29 Figure 19: Barramundi annual catch rates for fish caught and kept per trip ...................................30 Figure 20: Tagging grid maps covering the project area ..............................................................33 Figure 21: Tagging map showing the grid for locations where fish are tagged ................................33 McArthur River Monitoring page 3 Figure 22: Barramundi being tagged and measured ....................................................................34 Figure 23: Recaptured fish KA7381 showing algal growth on the tag.............................................34 Figure 24: Tag and recapture certificate introduced in 2012.........................................................35 Figure 25: Barramundi tagged each season................................................................................36 Figure 26: Grid locations where Barramundi have been tagged.....................................................36 Figure 27: Growth of Barramundi compared with days out ...........................................................38 Figure 28: Distance Barramundi moved compared with days out ..................................................38 Figure 29: Tagging and recapture locations for fish that moved ....................................................39 Figure 30: Movement of fish tagged in the Calvert River in 2007 ..................................................40 Figure 31: Movement of fish tagged in the McArthur River as part of MRM environmental monitoring 40 Figure 32: Tagged Barramundi being measured prior to release ...................................................41 Figure 33: Size range of all Barramundi measured from 2009-12..................................................41 Figure 34: Tagged and untagged Barramundi showing all fish and legal fish released ......................42 Figure 35 : Percentage of legal and juvenile Barramundi measured each year ................................42 Figure 36: River flows in the McArthur River and lengths of Barramundi over time ..........................44 Figure 37: Lengths of Barramundi over time showing recruits for the last 4 years...........................44 Figure 38: Locating small juvenile Barramundi is an important part of understanding recruitment ....45 Figure 39: Site of NT electrofishing surveys on the McArthur River at Borroloola in 2010 and 2012 ...46 Figure 40: Size range of fish tagged during the 2010 electrofishing survey ....................................46 Figure 41: Size range of Barramundi tagged and recaptured during the 2012 survey ......................47 Figure 42: Typical Golden Snapper tagged around Centre Island ..................................................47 Figure 43: Locations where Golden Snapper have been tagged.....................................................48 Figure 44: Sizes of measured Golden Snapper............................................................................49 Figure 45 : Sizes of Golden Snapper measured and kept .............................................................49 Figure 46: Comparison of recapture rates from 4 river systems....................................................50 Figure 47: Exploitation rates for the Daly, McArthur and Fitzroy rivers...........................................51 Figure 48: Comparison of Barramundi lengths for the McArthur, Fitzroy and Weipa Rivers for fish measured in 2011...................................................................................................................51 Figure 49: McArthur fishing trip data form .................................................................................55 Figure 50: Typical monthly tidal cycle for